For our coastal medical set, we acquired the Adventure Medical "Comprehensive Aquatic" Kit in a Pelican Case. We'll supplement this kit when we head offshore. We also have a small "daily use" kit containing seasickness medicine, band-aids, Neosporin, etc. conveniently located in the cockpit when we are on a passage. Our life raft also contains its own first aid kit.
So far, our medical training has included Red Cross basic first aid and resuscitation certification. We have attended the Pacific Cup "Safety at Sea" seminar and John & Amanda Neal's Cruising Seminars regarding medical issues and believe we have the knowledge and resources to handle most (common & simple) medical issues that may arise. Although there are more advanced courses where students can learn suturing, IV insertion, giving shots, etc. -- we will wait awhile before learning the advanced stuff.
Evacuation is probably our best course of action in the event of a severe sickness or injury. Our communication systems should be sufficient to help us arrange advanced treatment or evacuation. We also carry DAN emergency evacuation insurance.
Collision Damage & Hull Repair
If we accidentally hit a submerged or floating object and damage/pierce the hull, or a thru-hull leak develops, our first task is to stop water from flooding in so the bilge pumps can catch up. Then we (hope we) have all the tools and patching "stuff" necessary to effect an adequate temporary repair. We have a collision mat, two hull repair kits (including a half-gallon of two-part Splash Zone), wooden plugs fastened to each thru-hull, extra plugs, a chunk of marine plywood, and other materials that can be used for temporary patches.
Abandon Ship & Crew Rescue Gear
For a worse-case "abandon ship" scenario, we have a Winslow 6-person Super-light Coastal and Fishing life raft. We then had options added to make it appropriate for offshore use -- dual floor, extra canopy supports, and a few other changes Winslow recommended. We keep it in a soft case in a weather-protected locker in the cockpit.
We also have two ditch bags (large Pelican case and West Marine ditch bag) full of rescue and survival gear. The ditch bags contain most of the recommended gear, including an ACR GlobalFix 406 GPS-EPIRB, handheld GPS, handheld VHF (new Standard Horizon waterproof handheld VHF -- that takes AA batteries), and extra batteries, flares, and other quick-rescue/survival items.
The life raft itself contains a bunch of survival gear, and it received its first life raft servicing (at two years old) in the summer of 2003.
Before we left San Diego, we also added a new PUR (Katydyn) 06 manual watermaker to the Pelican ditch case. This will allow us to make drinkable fresh water from ocean salt-water.
We stow all this gear in the cockpit lazarette, consuming about 1/3 of the available space. The items are easy to access, and the ditch bag and Pelican case are fastened together on a tether, which is then connected to the life raft once deployed.
We can ready all of this for deployment and leave it in the cockpit until all other courses have been exhausted. Of course, we hope we'll never have to use any of this gear, but it nice to know it is there.